scholarly journals Effects of Substrate Temperature on Film Hardness and Hydrogen Content in Diamond-like Carbon Films Prepared with a Repetitive Nanosecond Pulsed Glow Hydrogen/Methane Discharge Plasma

2021 ◽  
Vol 16 (0) ◽  
pp. 1206038-1206038
Author(s):  
Katsuya IOKA ◽  
Yusuke KIKUCHI ◽  
Takuma MINE ◽  
Ryohei MASAI ◽  
Mitsuyasu YATSUZUKA
2010 ◽  
Vol 37 (8) ◽  
pp. 2063-2067
Author(s):  
罗乐 Luo Le ◽  
赵树弥 Zhao Shumi ◽  
仇冀宏 Qiu Jihong ◽  
方尚旭 Fang Shangxu ◽  
方晓东 Fang Xiaodong ◽  
...  

Author(s):  
S. Tshomo ◽  
A.K. Mohsin ◽  
B. Ismail ◽  
R. Hussin ◽  
M.n. Md.Yusuf ◽  
...  

Diamond-like carbon (DLC) thin films were deposited at different substrate temperatures using methane and hydrogen gas in DC-PECVD at 2x10-1Torr. From the light transmission using UV-VIS spectroscopy it was found that the optical transition had changed from allowed indirect transition to allowed direct transition as the substrate temperature increased. The Optical gap increased with temperature, highest of 3.034 eV was observed at 573 K, beyond which it dropped. Colour of the film changed from light brownish to a colourless transparent film in the higher temperature. The Urbach energy decreased from 1.25 eV to 0.75 eV with increasing substrate temperature till 573 K and a slight increase after it. This trend is attributed to change in sp3/sp2 ratio or change in structure. The cluster size decreases with temperature, resulting in larger band gap and the structure more ordered. Similar pattern is also witnessed in the emission spectrum of the photoluminescence.


1990 ◽  
Vol 5 (11) ◽  
pp. 2441-2444 ◽  
Author(s):  
W. Varhue ◽  
P. Pastel

The optical band gap, density, and hydrogen content of diamond-like carbon films have been controllably varied by rf biasing the substrate in an ECR discharge of pure methane. The optical band gap varied from 2.7 to 1.2 eV, the density from 1.4 to 2.2 g/cm3, and the atomic fraction of hydrogen from 50 to 5%. The range of measured values is in agreement with those predicted by both the random covalent network and defected graphite models.


2019 ◽  
Vol 825 ◽  
pp. 99-105
Author(s):  
Yutaroh Kimura ◽  
Xia Zhu ◽  
Hiromichi Toyota ◽  
Ryoya Shiraishi ◽  
Yukiharu Iwamoto ◽  
...  

This study was performed to improve the adhesiveness of a diamond-like carbon (DLC, a-C:H) layer film with an a-SiC interlayer. In previous studies, an a-SiC/DLC layer film was formed and changes in the DLC film structure and hardness caused by the thickness of the a-SiC layer were examined. After the a-SiC interlayer thickness increased and the G-peak position shifted to a lower frequency, the peak began shifting to higher frequencies. The G-peak position reached a minimum frequency at a film thickness of approximately 0.3 μm. In contrast, as the thickness of the a-SiC interlayer increased, the FWHM of the G-peak position increased almost monotonically and the number of sp3 bonds also increased. As the interlayer thickness increased, the hydrogen content in the DLC film increased, and then began decreasing, with the interlayer film thickness exhibiting a local maximum at approximately 0.3 μm. As for the DLC film hardness, a correlation between the hydrogen content and half width of the G-peak position was observed. When the hydrogen content was ≤40 at%, a positive correlation with the FWHM (G) was observed, and when the hydrogen content was 40 at% or above, a negative correlation with FWHM (G) was found. The adhesiveness of the DLC film and substrate was improved by forming an a-SiC thin film as an interlayer. The effects of the a-SiC thin film on DLC film quality were determined.


2002 ◽  
Vol 16 (06n07) ◽  
pp. 860-865 ◽  
Author(s):  
MANJU MALHOTRA ◽  
SATYENDRA KUMAR

We report on the growth of hydrogenated amorphous carbon (a-C:H) films, using a simple dc glow discharge plasma chemical vapor deposition method. A variety of complementary techniques were employed to analyze the properties of these films. a-C:H films having high fraction of tetrahedrally ( sp 3) bonded carbon atoms (~ 70%) and low hydrogen content (< 5at.%) were obtained. These films were characterized by a high optical bandgap ~ 2.7 eV, and refractive index (at 600nm) ~ 2.2. Growth of metastable diamond structure in a-C:H is attributed to energetic condensation of carbon containing ions in ( sp 3) configuration.


Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 360 ◽  
Author(s):  
Ruriko Hatada ◽  
Stefan Flege ◽  
Muhammad Naeem Ashraf ◽  
Arne Timmermann ◽  
Christoph Schmid ◽  
...  

Diamond-like carbon (DLC) films were prepared from a hydrocarbon precursor gas by plasma source ion implantation (PSII), in which the plasma generation and the film deposition were coupled; i.e., the plasma was generated by the applied voltage and no additional plasma source was used. Several experimental parameters of the PSII process were varied, including the sample bias (high voltage, DC or pulsed), gas pressure, sample holder type and addition of argon in the plasma gas. The influence of the deposition conditions on the carbon bonding and the hydrogen content of the films was then determined using Raman spectroscopy. Nanoindentation was used to determine the hardness of the samples, and a ball-on-disk test to investigate the friction coefficient. Results suggest that films with a lower sp2 content have both a higher hydrogen content and a higher hardness. This counterintuitive finding demonstrated that the carbon bonding is more important to hardness than the reported hydrogen concentration. The highest hardness obtained was 22.4 GPa. With the exception of a few films prepared using a pulsed voltage, all conditions gave DLC films having similarly low friction coefficients, down to 0.049.


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